The generators returned by the constructors are exhausted once all elements are retrieved; the optional start-th and end-th arguments can limit the range the generator walks across.

For reverse-vector->generator, the first value is the element right before the end-th element, and the last value is the start-th element. For all the other constructors, the first value the generator yields is the start-th element, and it ends right before the end-th element.